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3.3.2.4 PCM Interface
Signal Name Pin No I/O Signal level Comments
PCM_CLK 20 I or O
O/P : V
OL
max=0.2V
V
OH
min=2.8V
I/P : V
IL
max=0.8V
V
IH
min=2.1V
V
IH
max=3.7V
If unused keep pins open
PCM_IN 22 I
V
IL
max=0.8V
V
IH
min=2.1V
V
IH
max=3.7V
PCM_SYNC 24 I or O
O/P : V
OL
max=0.2V
V
OH
min=2.8V
I/P : V
IL
max=0.8V
V
IH
min=2.1V
V
IH
max=3.7V
PCM_OUT 26 O
V
OL
max=0.2V
V
OH
min=2.8V
3.3.2.5 General Purpose I/O and ADC
Signal Name Pin No I/O Signal level Comments
GPIO 1 - 9 2,4,12,
14,16,
33, 35,
37, 39
I or O
O/P : V
OL
max=0.2V
V
OH
min=2.8V
I/P : V
IL
max=0.8V
V
IH
min=2.1V
V
IH
max=3.7V
AIO_0, AIO_1 1, 3 I
Range 0 – 1.8V
3.3.2.6 Miscellaneous
Function Signal Name Pin No I/O Signal level Comments
Reserved USB D- 32 I
V
IL
max =0.3vdd_usb
V
IH
min =0.7vdd_usb
Normally inactive.
Pull to GND
through 10K
Reserved USB D+ 34 I
V
IL
max =0.3vdd_usb
V
IH
min =0.7vdd_usb
Normally inactive.
Pull to GND
through 10K
Reset RESET 13 I
Threshold 2.6V
Active HIGH
Terminology:
USB Signal Levels. vdd_usb refers to the internal voltage generated by the LDO regulator on the
module, which is typically 3.3V. Hence 0.3vdd_usb and 0.7vdd_usb correspond to 1.0V to 2.3V. If
Vcc falls below the recommended minimum of 3.6V, these values will be reduced.